Mower for Mowing Around Fence and Railing Posts

ABSTRACT

A mower assembly is provided for cutting around a post. A support structure supports the mower assembly in cantilever fashion. The mower assembly includes a plurality of mower units with each mower unit having a rotary blade. Two or more mower units cooperate to engage and cut around a post and, during the process, the entire mower assembly rotates about an axis enabling the mower units to encircle and efficiently cut grass and other vegetation about the post.

This application claims priority under 35 U.S.C. §119(e) from thefollowing U.S. provisional application: Application Ser. No. 61/523,581filed on Aug. 15, 2011. That application is incorporated in its entiretyby reference herein.

FIELD OF THE INVENTION

The present invention relates to mowers and more particularly

BACKGROUND OF THE INVENTION

The problems associated with mowing around fence posts and othervertical posts are well documented. There are numerous mower designsthat have attempted to solve this problem. But few mower designs havebeen successful. There are mowers that are designed to mow around afence or railing post. Few, if any, of these mowers make a clean andneat cut completely around the fence post or post railing.

SUMMARY OF THE INVENTION

The present invention relates to a mower design that produces a cleanand neat cut completely around a post. The mower of the presentinvention includes a support structure and a mower assembly secured andsupported by the support structure. The support structure is adapted tobe mounted to a tractor or other prime mover. The mower assemblyincludes a plurality of mower units with each mower unit having a rotaryblade. To mow around a post, the post is received between two mowerunits and the mower assembly rotates causing the mower units to bodilyrotate around the post, producing a clean and neat cut around the post.

In one embodiment, the mower assembly includes four mower units. Inoperation, two of the mower units engage and cut around a post and inthe process the mower assembly rotates approximately 180° to where thetwo mower units that formerly occupied a front portion of the mowerassembly now occupy a rear portion of the mower assembly. The two othermower units that formerly occupied the rear portion of the mowerassembly now occupy the front portion of the mower assembly and areappropriately positioned to engage the next successive post.

Other objects and advantages of the present invention will becomeapparent and obvious from a study of the following description and theaccompanying drawings which are merely illustrative of such invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the mower of the present invention.

FIG. 1A is a plan view of the mower of the present invention.

FIG. 1B is a plan view of a portion of the underside of the mower of thepresent invention.

FIGS. 2A-2I are a sequence of views showing the mower of the presentinvention mowing or cutting around a post.

FIG. 3 is a cross sectional view of a center mower unit of the mower.

FIG. 4 is a cross sectional view of an outer mower unit of the mower.

FIG. 5 is a perspective view of a second embodiment of the mower of thepresent invention.

FIG. 5A is a top plan view of the mower shown in FIG. 5 and which showsportions of the support structure.

FIG. 5B is a bottom view of the mower of the second embodiment.

FIG. 6A is a plan view of the mower of the second embodiment approachinga post.

FIG. 6B is a view similar to FIG. 6A but showing the post engaging thefront two mower units.

FIG. 6C is a view showing the post engaging the center mower unit.

FIG. 6D is a top plan view showing the mower assembly rotating clockwiseafter the post has engaged the center mower unit.

FIG. 6E shows the continued clockwise movement of the mower unit.

FIG. 6F shows further clockwise movement of the mower unit and with thepost being at approximately the 4 o'clock position.

FIG. 6G shows further clockwise movement of the mower assembly relativeto the position shown in FIG. 6F.

FIG. 6H shows the mower assembly after it has rotated approximately 180°and illustrates the post exiting the rear most mower units.

FIG. 6I is a figure similar to FIG. 6H showing the mower units in aclosed position and where the post has exited the rear portion of themower assembly.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

With further reference to the drawings, the mower of the presentinvention is shown therein and indicated generally by the numeral 10. Asdiscussed above, the mower 10 is designed to cut around posts such asfence posts and posts that support highway railings. Mower 10 includes asupport structure indicated generally by the numeral 12. See FIGS. 1 and1A. Support structure 12 is designed to attach to a tractor and toextend outwardly from the tractor. In one particular embodiment, thesupport structure 12 is designed to attach to the tractor and projectoutwardly from one side thereof. Secured to an outer end portion of thesupport structure 12 is a mower assembly indicated generally by thenumeral 14. Mower assembly 14 is supported by the support structure 12in cantilever fashion. As seen in FIGS. 1, 1A and 1B, the mower assembly12 includes a plurality of wheel assemblies or mower units. As will bediscussed herein, each wheel assembly includes a blade associatedtherewith for cutting grass and other vegetation disposed around a post.

First the support structure 12 will be discussed. Support structure 12includes an elongated arm 20. Arm 20 includes an outboard end portionthat attaches to the mower assembly 14. In addition arm 20 includes aninboard end portion that attaches at least indirectly to a tractor orother prime mover. The inboard end of the arm 20 is slidably containedin a receiver indicated generally by the numeral 22. See FIGS. 1 and 1A.Receiver 22 can be constructed in various ways. The function of thereceiver is to receive and hold the inboard end portion of arm 20 and toallow the arm to move or slide back and forth within the receiver. Inthe embodiment disclosed herein, the receiver 22 includes a series ofrollers for engaging the arm 20 and generally confining the arm. Therollers include side, top and bottom rollers and the rollers are spacedto receive the inboard end portion of the arm 20. Receiver 22 ispivotally mounted to a mounting frame indicated generally by the numeral24. This enables the receiver 22 to pivot and also allows the arm 20 toswing back and forth as the receiver pivots.

The mounting frame 24 supports the receiver 22 and permits the receiverto rotate about a generally vertical axis. Mounting frame 24, as seen inFIGS. 1 and 1A includes a pair of members 24A. Further the mountingframe 24 includes another member 24B. Extending upwardly from themounting frame 24 is a vertical bar 26. There is provided a connectingarm 28 that is slidably adjustable on the vertical bar 26 and whichextends from the vertical bar for connection to a tractor or other primemoving source. As seen in FIG. 1, the receiver 22 is suspended below themounting frame 24.

As seen in FIG. 1A, arm 20 includes an outer stop 20A. Stop 20A is fixedon arm 20 and restricts the outward movement of the arm 20. That is, ata selected point, the stop 20A will engage the receiver 22 and preventthe arm 20 from moving further outward, or generally left to right asviewed in FIG. 1A. Secured to the stop 20A is a spring 30. Spring 30extends from the stop 20A to the member 24B. Spring 30 has a tendency tobias the arm 20 toward an extended position with respect to the receiver22. In addition a guide member 32 is pivotally interconnected betweenstop 20A and the mounting frame 24. As will be appreciated fromsubsequent portions of the disclosure, as the arm 20 is extended andretracted with respect to the receiver 22, the guide member 32 willoscillate back and forth.

As briefly mentioned above, the mower assembly 14 is supported incantilever fashion on the outboard end of arm 20. As shown in FIGS. 1and 1A, the mower assembly 14 basically includes five wheel or mowerunits. These include a center wheel or mowing unit and four peripheralor outer mowing units. In some cases these subassemblies of the mowerassembly 14 is referred to as a wheel assembly and in other cases theymay be referred to as a cutting or cutter assembly.

Turning now to a discussion of the five mower units, there is provided acenter mowing unit indicated generally by the numeral 40. Projectingoutwardly from the center mowing unit 40 are four peripheral mowingunits indicated generally by the numerals 42, 44, 46 and 48. See FIG.1A.

With respect to center mowing unit 40, the same includes a main driveshaft 50 which extends through the outboard end of the arm 20. Anopening is provided in the outboard end of arm 20 and shaft 50 isrotatively journaled therein. By rotatively journaled it is meant thatthe shaft rotates within the opening in the outboard end of arm 20 andthat the arm 20 is effectively supported on the shaft. Shaft 50effectively couples the mower assembly 14 to the support structure 12.Fixed to shaft 50 is an upper sheave 52. Disposed below the upper sheave52 is a wheel 54. Wheel 54 is rotatively journaled on the shaft 50 suchthat the shaft 50 can turn independently of the wheel. Disposed belowthe wheel 54 is a lower plate 56. Shaft 50 extends through the wheel 54and through the lower plate 56. Shaft 50 is rotatively journaled in theplate 56. This means that the shaft 50 can rotate within an opening inthe plate but that the plate is supported on the shaft. Secured or fixedto the shaft 50 below the lower plate 56 is a lower drive sheave 58.Then secured or fixed to the shaft 50 below the lower sheave 58 is ablade 60. Finally, as particularly shown in FIG. 1B, disposed below theblade 60 and secured to the shaft 50 is a bumper 62. Bumper 62 can befixed or journaled to the shaft 50.

As seen in FIG. 1B, the underside of the lower plate 56 includes aseries of idlers 64. Idlers 64 are secured to the bottom of the plate 56and as will be discussed subsequently herein are utilized to guide adrive belt 130 that is effective to drive the outer or peripheralcutting assemblies 42, 44, 46 and 48.

Now attention will be directed at the individual peripheral mowing units42, 44, 46 and 48. Since each of these mowing units is similar inconstruction and operation, a description of one will suffice for all.Each peripheral mowing unit 42, 44, 46 and 48 includes a drive shaft 70.Journaled on the drive shaft 70 is a wheel 72. Fixed to the drive shaft70 underneath the wheel 72 is a sheave 74. Further fixed to the shaft 70below the sheave 74 is a cutting blade 76. A support arm 78 is journaledon the shaft 70 and extends inwardly toward the center mowing unit 40.Support arm 78 is pivotally connected to the plate 56 that forms a partof the center mowing unit 40. Thus it is appreciated that eachperipheral mowing unit can swing back and forth about the axis of apivot pin or connecting pin that connects the support arm 78 to theplate 56 of the center mowing unit 40. A spring 80 extends between thesupport arm 78 and the plate 56. This is shown in FIG. 1A. Spring 80biases the support arm 78 and in turn the peripheral or outer cutterassembly such that in a normal no load conditions the four outer mowingunits 42, 44, 46 and 48 are disposed as shown in FIG. 1A. That is in theno load position, the forward most mowing units 42 and 44 are biased toa position such that their respective wheels 72 engage. The same is truefor the rear most mowing units 46 and 48. Again see FIG. 1A.

An alignment assembly is incorporated into the mower 10 and is indicatedgenerally by the numeral 101. See FIGS. 1 and 1A. The alignment assembly101 includes a main arm 103 that is pivotally mounted to the arm 20 andprojects generally rearwardly therefrom. A secondary arm 107 is securedto arm 103 and extends therefrom. A pair of idlers 106 and 108 isrotatively mounted to the terminal ends of arms 103 and 107. As seen inthe drawings, idlers 106 and 108 are operative to engage the wheels 72of the respective outer mowing units 42, 44, 46 and 48 during theoperation of the mower 10. Further the alignment assembly 101 includes aspring 110 that is operatively connected between arm 103 and arm 20.Spring 110 is utilized to bias the alignment assembly 101 intoengagement with the respective wheels 72 during the cutting operating. Astop 112 also extends between the arm 20 and the arm 103 to effectivelylimit the counterclockwise movement of the alignment assembly 101, asviewed in FIG. 1A for example.

The mower 10 of the present invention is provided with a drive system.Various drive systems can be utilized and incorporated into the mower10. In the example shown herein, the drive system utilizes the hydraulicsystem of a tractor or prime mover for providing power for driving therespective mowing units. As seen herein, the drive system includes ahydraulic motor 120 that is mounted adjacent the arm 20. A pair ofhydraulic lines 121 leads to the hydraulic motor 120 and is typicallyconnected to the hydraulic system of the tractor or prime mover. A drivesheave 124 is connected to the hydraulic motor 120. A main drive belt127 is trained around the drive sheave 124 and also trained around thedrive sheave 52 of the center mowing unit 40. Therefore, it isappreciated that power generated by the hydraulic motor 120 istransferred via belt 127 to sheave 52 and shaft 50 of the center mowingunit 40.

Viewing FIG. 1B, it is seen that a second drive belt 130 is utilized todrive the respective outer cutting assemblies 42, 44, 46 and 48. Note inFIG. 1B how the second drive belt 130 is trained around the respectivesheaves 74 and the various idlers 64 disposed on the underside of plate56. It is appreciated that as the main drive shaft 50 of the centermowing unit 40 is driven, power is effectively transferred from thecenter mowing unit 40 to each of the peripheral or outer cuttingassemblies 42, 44, 46 and 48.

FIGS. 2A-2I show how the mower 10 operates with respect to a post P. Ina typical application, the mower 10 as shown in FIG. 2A is mounted tothe right side of a tractor and is disposed on the right side of thetractor as the tractor traverses the ground. In FIG. 2A, it is seen thatthe mower 10 is generally aligned with an oncoming post P. The idea isto align the mower 10 such that the post P will be in alignment with theinterface created by the engagement of the two forwardmost mowing units42 and 44. Note in FIG. 2B where the mower 10 has advanced to where thepost P engages both mowing units 42 and 44 and note that the post P atthis position is generally aligned with the center of the center mowingunit 40.

Turning to FIG. 2C, the mower 10 has further advanced. Post P hasengaged the two forward wheels 72 and caused the two forward mowingunits 42 and 44 to spread open. In this position, the blades 76associated with the forward most mowing units 42 and 44 effectively cutgrass on both sides of the post P. Eventually the mower 10 will advanceto where the post P is engaged by three wheels, the two wheels 72 of themowing units 42 and 44 as well as the center wheel 54. This is shown inFIG. 2D. At this point all three mowing units 40, 42, and 44 areeffectively cutting around the post P. At this point, the arm 20 isstill in its fully extended position. That is stop 20A engages thereceiver 22. As the mower 10 further advances forward from the positionshown in FIG. 2D, the outer cutting assemblies 42, 44, 46 and 48 startto rotate around the center mowing unit 40. This is illustrated in FIG.2E. Because of the geometry that exists between the support structure 12and the mower assembly 14, when the post P assumes the position shown inFIG. 2E, the arm 20 rotates at least slightly clockwise as viewed inFIG. 2E and the arm begins to slightly retract into the receiver 22.This gives rise to clockwise movement of the outer mowing units 42, 44,46 and 48. Thus as the mower 10 advances forward from the position shownin FIG. 2E, the outer cutting assemblies 42, 44, 46 and 48 continue torotate clockwise around the center mowing unit 40. In this process, theblades 76 associated with the outer mowing units 42 and 44 as well asthe blade 60 associated with the center mowing unit 40 continue to cutaround the post P. In FIG. 2F, the position of the arm 20 has reachedgenerally a maximum retracted position. From this point on, as the mower10 moves forward, the arm 20 will tend to extend. This is illustrated inFIG. 2G. Note as the mower 10 advances forward from the position shownin FIG. 2F to the position shown in FIG. 2G that the outer mowing units42 and 44 have now advanced to a position generally between the 3o'clock and 6 o'clock positions. All this time, the three mowing units40, 42 and 44 are cutting around the post P. Finally, in FIG. 2H a finalposition is reached where the former leading mowing units 42 and 44 arenow the trailing mower units. Still the post P is engaged with all threemowing units 40, 42 and 44.

As the mower continues to move forward from the position shown in 2H itis see that as the post P is cleared that the spring biased support arms78 will bias and bring the two cutting assemblies 42 and 44 back to ahome position.

In this position, the former trailing mowing units 46 and 48 now assumea leading orientation as they are now disposed in the front of the mower10. They in turn will take on the next succeeding post P.

It is appreciated that the wheels 72 and 54 of the respective mowingunits act to precisely space the respective blade 60 and 76 from thepost P. This allows precision cutting around the post P. Unlike somemowers of the prior art, the mower assembly 14 is effective to cutcompletely around the post. Indeed because of the nature of the designcertain areas around the post are cut multiple times by differentcutting assemblies during a single operation on a post.

In the embodiment illustrated in FIGS. 1-4 and discussed above, themower 10 is shown with four outer mowing units 42, 44, 46, and 48. Itshould be appreciated that the mower 10 could be provided with just twoouter mowing units. In this case, the two outer mowing units cooperatewith the center mowing unit 40 to cut around a post P. In this case,once a post P has been completely cut around such as shown in FIG. 2I,then the two outer mowing units would be required to rotate 180° so asto be disposed about the front of the mower 10 so as to be in a positionto operate on the oncoming post P. Thus, the major difference betweenthis embodiment and the embodiment discussed above, is that the twoouter cutting assemblies would have to be rotated to the front of themower 10 after completing a cutting operation so as to be in a positionto operate on the next oncoming post P.

A second embodiment for the mower is shown in FIGS. 5-61. The mowerassembly therein is indicated generally by the numeral 100. Mowerassembly 100 includes a pair of mower housings 102 and 104 that aretypically connected together in a scissor-life configuration. Mowerhousings 102 and 104 are connected together by a main central supportshaft 105. See FIGS. 5A and 5B. More particularly, the mower housings102 and 104 are journaled for rotation about the main support shaft 105.Although not particularly shown, the main support shaft 105 has threepulleys or sheaves secured thereto. There is a top sheave that is drivenfrom an external source and there are two other pulleys or sheaves thatare driven by the support shaft 105. As will be appreciated fromsubsequent portions of the disclosure, the mower assembly 100 issuspended in cantilever fashion from the support structure 200. Thesupport structure 200 that will be described subsequent herein includesa support beam 240 that receives and supports the central support shaft105. More particularly, the central support shaft 105 is journaled inthe outer end portion of the beam 240. As noted above, the main supportshaft 105 supports both mower housings 102 and 104 and parts thereof.

Turning to mower housing 102, it is seen that mower housing lies overthe lower mower housing 104. In any event, mower housing 102 includes afirst mower unit 102A. The first mower unit 102A is a peripheral mowerunit. Mower unit 102A includes a shaft rotatively supported in the mowerhousing 102 and there is provided a driven sheave connected to the shaftand there is also provided a rotary blade connected to the shaft. Inaddition, mower housing 102 includes a second mower unit 102B. This isalso a peripheral mower unit. Second mower unit 102B includes the sameshaft, pulley and rotary blade arrangement found in the first mower unit102A. Provided on the mower housing 102 is a pair of belt guards 102Cand 102D to shield or guard a belt that is utilized to drive the rotaryblades of the first and second mower units 102A and 102B.

The lower mower housing 104 includes three mower units, 104A, 104B and104C. As seen in FIG. 5B, mower units 104A and 104C are peripheral unitswhile mower unit 104B is deemed a central or center mower unit. There isalso provided two belt guards 104D and 104E secured on the lower mowerhousing 104 to guard or shield a belt drive that is utilized to drivethe respective rotary mower blades associated with the lower mowerhousing 104.

As shown in FIG. 5A, the respective peripheral mower units are shown ina closed position. The front mower units 102A and 104A are engaged as isthe rear peripheral mower units 102B and 104C. See FIG. 5B. In order tomaintain the mower units in a closed position, there is provided a pairof biasing springs 113 and 114. See FIG. 5A. The biasing springs 113 and114 are interconnected between front and back portions of the mowerhousings 102 and 104.

Like the first embodiment shown in FIGS. 1-4, the second embodimentincludes an alignment mechanism for maintaining the mower assembly 100in a proper forward alignment such as shown in FIG. 5A. The alignmentmechanism includes a control arm 109 that is pivotally connected to thesupport beam 240 and extends rearwardly form the support beam. A spring111 is interconnected between the support beam 240 and the control arm109 which tends to bias the control arm 109 towards the right as viewedin FIG. 5A. A pair of stops 109A and 109B is secured on the control arm109 and is spaced to engage the left side of the trailing mower unit.

The mower assembly 100 is hydraulically driven. There is provided ahydraulic motor 116. See FIG. 5A. Hydraulic motor 116 is controlled by amanually actuated control valve 115 (FIG. 5). Hydraulic motor 116 drivesa sheave 118 (FIG. 5B). A belt guard 119 shields a drive belt 122 whichis trained around sheave 118 and drives a pulley or sheave fixed to themain shaft 105 of the mower assembly 100. As seen in FIG. 5B, an idler123 engages drive belt 122 to maintain the belt taut. There are also twoadditional sheaves or pulleys secured to the main shaft 105. As seen inFIG. 5B, there are two driven belts 126 and 128 trained around these twoadditional pulleys or sheaves on the main shaft 105. One of the beltsdrives the mower units of the mower housing 102. The other belt drivesthe mower units of the mower housing 104. Again, there are numerousidlers that engage belts 126 and 128 as they are trained around numerousseparate sheaves of the three mower units of mower housing 104.

In the embodiments illustrated herein, the mower assembly 100 is shownwith a support structure 200 that is designed to attach the mowerassembly to a tractor. It should be understood and appreciated that themower assembly disclosed herein can be incorporated into aself-propelled machine. In the case of the FIG. 5 embodiment, thesupport structure 200 differs from the support structure associated withthe FIG. 1 embodiment. In any event, the support structure 200 extendingor associated with the mower assembly 100 shown in FIG. 5 is designed toattach to a tractor. With reference to FIG. 5, the support structure isindicated generally by the numeral 200 and includes a tractor mount 201.The tractor mount 201 includes two opposed plates that bolt or secure tothe frame structure of the tractor.

Secured to the tractor mount 201 is a main frame structure 202. As canbe seen in FIG. 5, the main frame structure 202 is a ground engagingframe structure that supports the mower assembly 100. Main framestructure 202 includes a main frame 204 that joins a cross member 205 toform a generally T-shaped structure. The cross member 205 supports apair of wheels 206.

Supported on the main frame structure 202 is a mower lift assemblyindicated generally by the numeral 210. Mower lift assembly 210 isdetachably connected to the tractor. Note in FIG. 5 where the mower liftassembly 210 includes an attaching plate 212 that is attachable to thetractor. Secured to the attaching plate 212 is a lift arm support 218.Pivotally connected to the lift arm support 218 is a lift arm 214 thatis also pivotally connected to a clevis or bracket structure thatextends upwardly from the main frame 204. A hydraulic cylinder 216 issupported on the main frame structure 202 and is operatively connectedto the lift arm 214 to raise and lower the same. The hydraulic cylinder216 is typically powered with hydraulics associated with the tractor.There is a spring 220 interconnected between the lift arm support 218and the lift arm 214. In addition, there is a balancing spring 222disposed generally over the lift arm 214 which tends to support themower assembly 100 and to maintain the wheels 206 in engagement with theground as the mower assembly 100 traverses the ground.

Projecting forwardly from the main frame 202 is a pair of pivotallymounted control arms 230 and 232. This is best seen is FIG. 5A. Notethat the control arms 230 and 232 are generally disposed in parallelrelationship and are pivotally connected to other structures at oppositeends. A pair of springs 234 is interconnected between the two controlarms 230 and 232. At the outer ends of the control arms 230 and 232there is provided a pair of attaching brackets 236. Attaching brackets236 are pivotally connected to the outer ends of the control arms 230and 232. Attaching brackets 236 are in turn attached to the main supportbeam 240 which extends outwardly from the attaching brackets. Note inFIG. 5A where the main support beam 240 extends in cantilever fashionfrom the attaching brackets 236. As discussed before, the main supportbeam 240 supports the entire mower assembly 100 via the main supportshaft 105. More particularly, the main support shaft 105 is rotativelyjournaled in the remote or outer end of the main beam 240.

The principle function of the two control arms 230 and 232 is to biasthe main support beam 240 outward or in the left-to-right direction asdepicted in FIG. 5A. This causes the center mower unit 104B to tend tohug a post P as the mower assembly 100 engages the post and rotatesaround the post.

Turning to FIG. 6A-61, there is a sequence of plan views showing themower assembly 100 cutting grass or other material such as vegetationaround a post P. Note FIG. 6A shows the mower assembly 100 in a normalposition not engaged with a post P. In this normal position, the mowerassembly is aligned with an oncoming post P. Note that the wheels 206are aligned with the direction of travel as illustrated by the outerarrow. However, in this case, the control arms 230 and 232 are slightlyangled.

FIG. 6B shows the mower assembly 100 engaging the oncoming post P. Herethe post P has engaged mower units 102A and 104A and has caused them tobe slightly spread. As discussed above, the mower housings 102 and 104are biased towards a closed position such as shown in FIG. 6A. As thepost engages the mower units 102A and 104A, the post causes the mowerunits to move from the closed position towards an open position. As themower assembly 100 is further advanced towards the post P, it is seenthat the post will eventually cause the mower units 102A and 104A toassume their open position. This is shown in FIG. 6C. At this position,the post has engaged the center most mower unit 104B. Note that in thisposition the control arms 230 and 232 have pivoted slightly from theposition shown in FIG. 6B. In particular, the forward portions of thearms 230 and 232 have moved more to the left as viewed in FIG. 6C. Thismeans that the main beam 240 and the mower unit 100 have moved slightlyto the left compared to the position that these components assumed inFIG. 6B.

As the mower unit 100 moves forward from the position shown in FIG. 6C,the engagement of the post P with the central portion of the mowerassembly will cause the mower assembly to bodily rotate clockwise. Thisis shown in FIG. 6D. As the mower assembly 100 rotates, the respectivemower units 102A, 104A and 104B will cut grass or other material aroundthe post P. Note also in FIG. 6D where the main support beam 240 isfurther shifted to the left. Thus as the mower assembly 100 rotatesclockwise, the beam 240 moves to the left and hence the control arms 230and 232 pivot to the position shown in FIG. 6D. All the time the controlarm 230 and 232 are biasing the main beam 240 to the right and urgingthe center mower unit 104B to engage and hug the post P as the mowerassembly 100 rotates around the post.

In FIG. 6E, the mower assembly 100 has further rotated clockwise. Againin the process mower unites 102A, 104A and 104B have continued to cutgrass and other material lying around the post P. Control arms 230 and232 have further rotated in response to the mower assembly engaging thepost and rotating around the post. Still the control arms 230 and 232effectively bias the main beam 240 towards the right as viewed in FIG.6E such that the mower assembly 100 is caused to hug the post P duringthe course of its rotation.

In FIG. 6F, the mower assembly 100 has further rotated to where the postlies at approximately the 4 o'clock position. Here the mower unit 102Alies at approximately the 6 o'clock position and mower unit 104A lies atapproximately the 3 o'clock position. Once the post lies past the 3o'clock position, the control arms 230 and 232 tend to move back in theopposite direction as the biasing effect of the arms causes the mowerassembly 100 and the main support beam 240 to move to the right asviewed in FIG. 6F.

In FIG. 6G, the mower assembly 100 has rotated to where the post isgenerally halfway between the 3 o'clock position and the 6 o'clockposition. Again, it is noted that the control arm 230 and 232 aretending to rotate to the right and the mower assembly and main supportbeam 240 are also being moved to the right causing the mower assembly100 to continue to engage and mow around the post P.

In FIG. 6H, the mower units 102A and 104A have rotated bodilyapproximately 180°. The post P is still being contacted by mower units102A and 104A but are about to exit from between the two mower units asthe mower assembly 100 moves forward.

FIG. 6I shows the post P having exited from between mower units 102A and102B. Note that after the post has exited the mower units 102A and 102Bthat the springs 113 and 114 causes the mower units 102A and 104A tomove to their closed position. At this time the control arms 230 and 232assume essentially the same position shown in FIG. 6A. Note that mowerunits 102B and 104C have now assumed the forward most position and areproperly positioned to receive the next succeeding post.

Therefore, it follows that as each post is contacted by the mowerassembly 100 that the two leading mower units will engage and cooperateto cut grass or other vegetation around the post P. As the entire mowerassembly rotates, the two leading mower units will effectively circlethe post and the rotary blades forming a part of the mower units willcut extremely close to the post P. In the embodiment illustrated, thepost is effectively encircled by the two leading mower units and thecentral mower unit 104B. It should be appreciated, however, that thecentral mower unit 104B may not be essential to achieving a complete cutaround the post P. It is believed that two peripheral mower units suchas mower units 102A and 104A, through cooperation, will effectively cutgrass and other vegetation very close to the post P without the need ofa third central mower unit.

One of the advantages of the mower assembly 100 of the present inventionlies in providing at least four mower units. This is because once twomower units have engaged a post and cut around the post, then the othertwo mower units, through bodily rotation, have been positioned forwardlyin the mower assembly 100 such that they are ready to take on the nextsucceeding post. This greatly increases the efficiency of the mowerassembly 100 and decreases the rotation cycles required for a givennumber of posts P.

At various places in the specification and claims, it is stated that themower assembly 100 is bodily rotatable. In some cases it is noted thatthe mower assembly or a mower unit is bodily rotatable relative to thesupport structure or that the mower units are bodily rotatable about apost. This means that the mower assembly or the mower units rotate as aunit.

The present invention may, of course, be carried out in other ways thanthose specifically set forth herein without departing from essentialcharacteristics of the invention. The present embodiments are to beconsidered in all respects as illustrative and not restrictive, and allchanges coming within the meaning and equivalency range of the appendedclaims are intended to be embraced therein.

1. A rotary mower system for mowing around a post, comprising: a supportstructure; a rotary mower assembly secured to the support structure andbodily rotatable relative to the support structure, the mower assemblycomprising: i. first, second, third and fourth mower units with eachmower unit having a rotary blade; ii. the first and second mower unitsbeing moveable relative to each other and moveable between a closedposition and an open position wherein in the closed position the firstand second mower units lie relatively close to each other and in theopen position, the first and second mower units are spaced apart suchthat the post can pass between the first and second mower units as themower assembly is advanced; iii. a biasing structure for biasing thefirst and second mower units towards the closed position but permittingthe first and second mower units to move from the closed position to theopen position in response to the post passing between the first andsecond mower units; and iv. the third and fourth mower units beingmoveable relative to each other and moveable between a closed positionand an open position wherein in the closed position the third and fourthmower units lie relatively close to each other and in the open position,the third and fourth mower units are spaced apart such that the post canpass between the third and fourth mower units; v. a biasing structurefor biasing the third and fourth mower units towards the closed positionbut permitting the third and fourth mower units to move from the closedposition to the open position in response to the post passing betweenthe third and fourth mower units; vi. the mower assembly including thefirst, second, third and fourth mower units being bodily rotatable inresponse to two of the mower units engaging the post such that as thepost is engaged, the mower assembly bodily rotates such that at leasttwo mower units engage the post and cut grass or other material aroundthe post as the mower assembly bodily rotates; and vii. wherein themower assembly when cutting around the post bodily rotates approximately180° such that the mower units, formerly assuming the rearmost positionbefore rotation, now occupy the forwardmost position after rotation. 2.The rotary mower system of claim 1 including a fifth mower unit thatassumes a generally central position with respect to the first, second,third and fourth mower units.
 3. The rotary mower system of claim 1wherein the support structure supports the mower assembly in cantileverfashion; and wherein the mower assembly rotates about a support shaftsupported by the support structure.
 4. The rotary mower system of claim1 wherein the support structure includes a biasing mechanism that urgesthe mower assembly to engage and maintain relatively close contact withthe post as the mower assembly bodily rotates around the post.
 5. Therotary mower system of claim 1 wherein the first and second mower unitsbodily rotate approximately 180° in the course of cutting materialaround the post.
 6. The rotary mower system of claim 1 wherein the mowerassembly is supported in cantilever fashion from the support structureand is rotatable about a vertical axis.
 7. The rotary mower system ofclaim 2 wherein the vertical axis forms an axis of rotation for a rotaryblade of the fifth mower unit.
 8. The rotary mower system of claim 1wherein the rotary mower system is configured to be mounted to a tractorand to extend from either side of the tractor, and wherein the first andsecond mower units are mounted to the support structure such thatengagement with the post causes the first and second mower units torotate in a general direction away from the tractor as the first andsecond mower units cut material around the post.
 9. The rotary mowersystem of claim 1 wherein the first and second mower units share acommon housing and wherein the third and fourth mower units share acommon housing.
 10. The rotary mower system of claim 9 wherein the twohousings are rotatably mounted on a central shaft.
 11. A rotary mowersystem that has the capability of cutting grass or other material arounda post, comprising: a support structure; a mower assembly rotatablymounted to the support assembly and bodily rotatable 360° about an axis;the mower assembly including: i. a first mower housing having two spacedapart mower units with each mower unit having a rotary blade; ii. thefirst mower housing being rotatable about the axis; iii. a second mowerhousing having two spaced apart mower units where each mower unitincludes a rotary blade; iv. the second mower housing being rotatableabout the axis; v. wherein the first mower housing is rotatable relativeto the second mower housing and wherein the two mower housings aremoveable between a closed position and an open position; vi. a biasingstructure operatively connected to the first and second mower housingsfor biasing the first and second mower housing towards the closedposition and wherein the biasing structure permits the first and secondmower housings to move from the closed position to the open position inresponse to the post passing between the first and second mowerhousings; and vii. wherein advancing the mower housings such that thepost engages the first and second mower housings causes the mowerhousings to move from the closed position to the open position and torotate and move around the post such that at least two of the mowerunits cooperate to cut material around the post.
 12. The rotary mowersystem of claim 11 wherein the first and second mower housings inresponse to engaging the post rotate approximately 180° and thereafterthe first and second mower housings rotate another 180° in response toengaging a succeeding post.
 13. The rotary motor system of claim 11wherein the support structure includes a moveable support arm thatsupports the mower assembly in cantilever fashion and is moveablelaterally back and forth as the mower assembly rotates about the axis.14. The rotary mower system of claim 13 wherein the support structurefurther includes a ground engaging frame and wherein the moveablesupport arm is operatively connected to the ground engaging frame andprojects therefrom.
 15. A method of cutting grass or other materialaround a post with a mower assembly comprising: advancing first andsecond mower units of the mower assembly towards the post with eachmower unit including a rotary blade; engaging the post with a throatarea defined between the first and second mower units; advancing thefirst and second mower units such that the post spreads the first andsecond mower units, and the first and second mower units cut grass orother material around portions of the post; advancing third and fourthmower units of the mower assembly towards a succeeding post with eachmower unit including a rotary blade; engaging the succeeding post with athroat area defined between the third and fourth mower units; advancingthe third and fourth mower units such that the succeeding post spreadsthe third and fourth mower units, and the third and fourth mower unitscut grass or other material around portions of the post; and bodilyrotating the mower assembly and the first, second, third and fourthmower units such that in cutting grass or other material around the postthe first and second mower units function to cut the grass or othermaterial around the post and bodily rotate approximately 180° andthereafter the third and fourth mower units which formerly assumed arearmost position have been rotated to assume a forwardmost position andare in position to engage the succeeding post and cut grass or othermaterial around portions of the succeeding post as the mower assembly isbodily rotated.
 16. The method of claim 15 wherein the mower assemblyincludes a fifth center mower unit that generally lies between thefirst, second, third and fourth mower units and wherein the fifth mowerunit engages the post when the first and second mower units are rotatingaround the post, and engage the second succeeding post when the thirdand fourth mower units are engaging and rotating around the succeedingpost.
 17. The method of claim 16 wherein the first, second, third andfourth mower units form a part of the mower assembly that is rotatableabout a vertical axis and wherein the method includes rotating the mowerassembly approximately 180° when cutting the grass or other materialaround the post and thereafter rotating the mower assembly approximatelyanother 180° while cutting grass or other material around the succeedingpost.
 18. The method of claim 17 wherein prior to cutting grass or othermaterial around the post the first and second mower units assume a frontposition and the third and fourth mower units assume a rearwardposition; and wherein after cutting the grass or other material aroundthe post the first, second, third and fourth mower units have rotatedapproximately 180° to where the third and fourth mower units assume thefront position and the first and second mower units assume a rearwardposition.
 19. The method of claim 15 wherein the first, second, third,fourth mower units bodily rotate about a generally vertical axis wheneither the first and second mower units or the third and fourth mowerunits are cutting grass or other material around the post.
 20. Themethod of claim 19 wherein the axis of rotation of the mower assemblycoincides with the axis of a drive shaft that is secured by the supportstructure and which supports the mower assembly.
 21. A rotary mowersystem for cutting grass around posts comprising: a support structure; amower assembly pivotally mounted to the support structure and rotatableas a unit about an axis; the mower assembly including first, second,third and fourth mower units with each mower unit having a rotary blade;and the mower assembly configured to engage a first post and rotateapproximately 180° such that during the rotation the first and secondmower units engage the first post and cut grass around the first post,and wherein in the course of rotating the approximately 180°, the mowerassembly repositions the third and fourth mower units to engage a secondpost, and wherein the mower assembly, in response to engaging the secondpost, rotates another approximately 180° and during this rotation thethird and fourth mower units engage the second post and cut grass aroundthe second post.
 22. The rotary mower system of claim 21 wherein themower assembly includes a fifth mower unit disposed generally betweenthe first, second, third and fourth mower units and which cooperateswith the first, second, third and fourth mower units to cut grass aroundthe respective posts.
 23. The rotary mower system of claim 21 wherein atleast a portion of the support structure having the mower assemblysupported thereby is moveable in response to the mower assembly engagingone of the posts such that as the mower assembly rotates, the mowerassembly also moves at least slightly generally laterally.
 24. Therotary mower system of claim 21 wherein the first and second mower unitsform a part of a first mower housing and wherein the third and fourthmower units form a part of a second mower housing, and wherein the firstand second mower housings are secured together in a scissorsconfiguration.
 25. The rotary mower system of claim 21 wherein the firstand second mower units are biased to a closed position and configured toreceive the first post therebetween wherein when the first post movesbetween the first and second mower units, the first and second mowerunits move to an open position; and wherein the third and fourth mowerunits are biased to a closed position and wherein when the second postmoves between the third and fourth mower units, the third and fourthmower units move to an open position such that the second post can movebetween the third and fourth mower unit.